Skip navigation

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

URL of this page: //medlineplus.gov/ency/patientinstructions/000488.htm

Allergies, asthma, and molds

In people who have sensitive airways, allergy and asthma symptoms can be triggered by breathing in substances called allergens, or triggers. It is important to know your triggers because avoiding them is your first step toward feeling better. Mold is a common trigger.

Molds

When your asthma or allergies become worse due to mold, you are said to have a mold allergy.

There are many types of mold. They all need water or moisture to grow.

  • Molds send out tiny spores that you cannot see with the naked eye. These spores float through the air, outdoors and indoors.
  • Mold can begin growing indoors when the spores land on wet surfaces. Mold commonly grows in basements, bathrooms, and laundry rooms.

Controlling Mold Indoors

Fabrics, carpets, stuffed animals, books, and wallpaper can contain mold spores if they are in damp places. Outdoors, mold lives in the soil, on compost, and on plants that are damp. Keeping your house and yard drier will help control mold growth.

Central heating and air-conditioning systems can help control mold.

  • Change furnace and air conditioner filters often.
  • Use high efficiency particulate air (HEPA) filters to best remove mold from the air.

In the bathroom:

  • Use an exhaust fan when you shower or take baths.
  • Use a squeegee to wipe water off shower and tub walls after you bathe.
  • Do not leave damp clothes or towels in a basket or hamper.
  • Clean or replace shower curtains when you see mold on them.

In the basement:

  • Check your basement for moisture and mold.
  • Use a dehumidifier to keep the air drier. Keeping indoor moisture levels (humidity) at less than 30% to 50% will keep mold spores down.
  • Empty dehumidifiers daily and clean them often with a vinegar solution.

In the rest of the house:

  • Fix leaky faucets and pipes.
  • Keep all sinks and tubs dry and clean.
  • Empty and wash the refrigerator tray that collects water from the freezer defroster often.
  • Frequently clean any surfaces where mold grows in your house.
  • Do not use vaporizers for an extended time to manage symptoms during asthma attacks.

Outdoors:

  • Get rid of water that collects around the outside of your house.
  • Stay away from barns, hay, and wood piles.
  • Do not rake leaves or mow grass.

Alternative Names

Reactive airway - mold; Bronchial asthma - mold; Triggers - mold; Allergic rhinitis - pollen

References

American Academy of Allergy Asthma & Immunology website. HOME allergy management. acaai.org/resources/tools/home-allergy-management. Accessed July 22, 2022.

Cipriani F, Calamelli E, Ricci G. Allergen avoidance in allergic asthma. Front Pediatr. 2017;5:103. PMID: 28540285 pubmed.ncbi.nlm.nih.gov/28540285/.

Matsui E, Platts-Mills TAE. Indoor allergens. In: Burks AW, Holgate ST, O'Hehir RE, et al, eds. Middleton's Allergy: Principles and Practice. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 28.

Review Date 6/7/2022

Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

Related MedlinePlus Health Topics